The invention pertains to control systems and, more particularly, to methods and apparatus for distributing, installing and/or validating components of such systems.
The terms xe2x80x9ccontrolxe2x80x9d and xe2x80x9ccontrol systemsxe2x80x9d refer to the control of a device or system by monitoring one or more of its characteristics. This is used to insure that output, processing, quality and/or efficiency remain within desired parameters over the course of time. In many control systems, digital data processing or other automated apparatus monitor the device or system in question and automatically adjust its operational parameters. In other control systems, such apparatus monitor the device or system and display alarms or other indicia of its characteristics, leaving responsibility for adjustment to the operator.
Control is used in a number of fields. Process control, for example, is typically employed in the manufacturing sector for process, repetitive and discrete manufactures, though, it also has wide application in electric and other service industries. Environmental control finds application in residential, commercial, institutional and industrial settings, where temperature and other environmental factors must be properly maintained. Control is also used in articles of manufacture, from toasters to aircraft, to monitor and control device operation.
Digital data processing is firmly entrenched in the control systems. System designers increasingly rely on software to add functionality and flexibility to their systems. The installation and validation of process control system components, for example, has generally been quite simplistic. When a new hardware component is to be installed, an operator or test engineer must take the system offline, install the new component, bring the system back online, and monitor the operation of the component. If satisfied, the engineer makes the installation permanent.
The I/A Series process control systems, manufactured by the assignee hereof, represent a major advance in this technology. They utilize a fault-tolerant architecture in which each control processor (CP), for example, has a redundant, shadow partner. Either of the partners can be replaced or updated while the system is still in operation. To this end, one of the CPs is placed in active mode, while its partner is being upgraded. The upgraded unit is then brought on-line, but only in shadow mode. Its operation is monitored by the engineer or operator, e.g., who compares its output with that of the active CP. If satisfied with the upgraded unit, the engineer can make it active, so that the remaining original CP can be upgraded. Redundant, fault-tolerant operation resumes once both CPs are similarly upgraded.
While the prior art techniques have proven effective to date, the ever increasing complexity of control systems render those techniques problematic. The physical replacement of hardware components, for example, can render maintenance unduly costly. This is exacerbated if the engineer must remain at a remote site until validation of the replacement is complete.
The replacement of software components is only somewhat less demanding. Apart from the aforementioned I/A Series systems, the prior art typically demands that an entire system be upgraded or, at least, taken off-line in order for an upgrade to be performed and tested. Moreover, the replacement of software components in prior art systems requires that the engineer be present at the replacement site, remaining there until the replacement is validated.
An object of this invention is to provide methods and apparatus that overcome these shortcomings. More particularly, an object is to provide improved methods and apparatus that facilitate the distribution, installation and validation of control systems and components.
A further object of the invention is to provide such methods and apparatus as facilitate the installation of components into active or on-line control systems.
A still further object of the invention is to provide such methods and apparatus as facilitate the distribution of control system components, e.g., from a manufacturer""s site, and their installation, e.g., at a remote site.
Yet a still further object of the invention is to provide such methods and apparatus as can be readily implemented on existing digital data processing apparatus or special purpose control apparatus.
Still yet further related objects of the invention are to provide such methods and apparatus as can be applied in process control systems, environmental control systems, and the like.
The foregoing are among the objects attained by the invention, which provides in one aspect a control system with blocks or other components that facilitate validation of their own replacements. Further aspects of the invention provide control systems in which the components to be validated are downloaded and installed from a remote site, e.g., via e-commerce transaction.
Thus, in one aspect, the invention provides a control system that includes first and second control components, e.g., flow control objects for a process control system. The first component is coupled to a third control component, with which it transfers information, e.g., as part of an active or ongoing control process. The third component can be, for example, a temperature control object with which the first component (e.g., a flow control object) is in a cascaded arrangement. The second component can be, for example, an update or other potential replacement for the first component. Thus, for example, if the first component is a flow control object, the second component can be a similar control object with new or improved functionality.
The first and/or second components of a control system according to this aspect of the invention can effect substitution of the second component for the first. More particularly, they can effect coupling of the second component for information transfer with the third component and decoupling of the first component from such transfer with the third component. Preferably, such coupling and decoupling occur while the control system remains active.
According to a related aspect of the invention, prior to its substitution for the first component, the second component is coupled to receive information from the third component and/or any sources from which the first component receives information. The second component, however, is at least temporarily prevented from outputting information to any sinks to which the first component sends information. Instead, the output of the second component can be routed, along with that of the first component, to one or more comparators. These can reside elsewhere in the control system, e.g., in a supervisor object, or within the first and/or second components themselves. Substitution of the second component for the first rests on the success of comparison of their outputs and, in most applications, on confirmation by the operator or test engineer.
By way of example, a comparator can check the output of a newly installed flow control object against the output of an old object it is intended to replace. The comparator can notify the operator of the results of the comparison and, if the operator approves, the new object can be substituted for the old.
Further aspects of the invention provide a control system as described above in which one or more stores, e.g., pointers, symbols, variables, matrices, arrays, tables, records, databases, files, or other information stores, identify relationships between components and, more particularly, their respective sources and sinks. A list maintained in the first component, for example, can identify its various parameters that are sinks for the third component and, likewise, parameters in the third (or other components) for which it (the first component) is the source. Substitution of the second component for the first may be effected, for example, by replacing all connections to/from the first component with connections to/from the second component.
Still further aspects of the invention provide a control system as described above in which the first and second components are resident on a control processor, a xe2x80x9csmartxe2x80x9d field device, or on another digital data processor-based control device. The configured second component can be downloaded to that device, e.g., from a control system work station, while the control system is active and while the first component is operational, e.g., exchanging information with the third component. By way of further example, downloading from a manufacturer""s site to the workstation can be effected as part of a contracted-for maintenance transaction, an upgrade transaction and/or as part of an e-commerce transaction, e.g., between the customer and the manufacturer. Such downloading, moreover, can be instigated by the customer or, automatically, by the first component or a software agent within the control system.
Yet still further aspects of the invention provide methods for control and methods for distributing and/or installing control components paralleling the operations described above.